Factors controlling the surface growth of the mandible may operate through its membranous capsule, the periosteum. To investigate the role of periosteal attachment, tension, and migration in the growth of the membranous facial bones, the following objectives have been established for the proposed reseaach: the development of a periosteal migration map of the growing mandible; the determination of the biochemical structure of the mandibular periosteum; the study of the synthesis of macromolecules in free periosteal segments in vitro; the determination of cross linking profile differences between periosteum of young and non-growing animals; and the description of the alterations in periosteal cell mitosis and migration patterns following manipulations in living animals. The results of these experiments in combination with an examination of sites of bone deposition and resorption and muscle attachments may elucidate how the periosteal interface receives stimuli and translates them into bone form. Such information may subsequently make it possible to alter facial growth more successfully during the treatment of craniofacial malformations and skeletal disproportions.